Red tetrazo dye.



' UNITED STATES EATENT OFFICE.

HUGO W1TTER, 'OF LEVERKUSEN, NEAR-COLOGNE, GERMANY, ASSIGNOR TOf-FARBENEABRIKEN, VORM. FRIEDR. BAYER & 00., OF ELBERFELD, GERMANY, 'A'CORPORATION OF GERMANY.

RED TE TRAZQ DYE.

Specification of Letters "fiatenta I Patented Jan. 22, 1907.

I Application filed October 15, 1906- Serial No. 339,024.

To all whom if -ma,y.00ncern:

Be it known that I, HUGO'WITTER, a citizen of the German Empire, residing at Leverkusen, near Cologne, Kingdom of Prussia,

Germany, have invented new and useful Improvements in Red Tetrazo Dye, of which the ollowing is a specification.

-My invention relates to the pre aration of a new tetrazo dyestuff which is 0 tained by to combining one molecule of the tetrazo compound of benzidin with one molecule of 2- naphthylamin-3b-disulfonic acidand (in acid solution) with one molecule of 2-amino- 8-naphthol-6-sulfom'c acid, or vice- Versa.

' The dye thus obtained dyes cotton bluishpecil shades remarkable for good fastness to lg t. 5

In order to illustrate my invention, the following example is given, the parts being by weight: 18.4 parts of benzidin arediazotized in the usual manner by means of 13.8 parts of sodium nitrite and the necessary quantity of hydrochloric acid. The resulting tetrazo compound is then introduoed into a well- 2 5 cooled solution of thirty-one arts of 2- naphthylamin-3.(i 'disulfonic aci containing an excess of sodium acetate. When the for- 'mation of the intermediate compound is C0111".

plete, a neutral solution of twenty-four arts 0 of 2-amin0-8 naphthol6-sulfonic is a ded,

and the mixture 1s stirred for some time and is then heated to oentigrade untilno more diazo compound can be found. It is rendered alkalineby the addition of sodium 3 5 carbonate, and the dyestuff is precipitated by the addition of common salt, filtered off,

and dried. It dyes cottonclear bluish-red shades.

The process is carried out in an analogous mannerby combining the tetrazo compound at first with the 2-amino-8-naphthol-6-sulfonic acid and then with the 2- naphthylamin- 3.6-disulfonic acid.-

The new tetrazo dyestuff is after being dried and pulverized in the shape of its so- 'what I claim as new, and desire to secure by Letters Patent, is

The herein-described tet'razo, dyestuff obtainable by combining tetrazotized benzidin with one molecule of 2-na'phthylamin-3.6- disulfonic acid and in acid solution with one molecule of 2- amino-8-naphthol-6'-sulfonic acid, which dyestuff is, after being dried and pulveriied, in the shape of its sodium salt a dark powder soluble in water with a bluishred color and in, concentrated sulfuric acid with a greenish-blue color; dyeing cotton bluish-red shades; and yielding upon reduction withstannous chlorid and hydrochloric 7o acid paraara-diaminodiphenyl, 1.2 diami- I no-8-na ht ol-6-sulfonic acid and 1.2-naphthyleniamin-3.6-disulfonic acid, substantially as hereinbefore described. f

In testimony whereofl have hereunto-set '75 my hand in the presence of two subscribing witnesses.

'HUGrCl WITTER. [L. s.]

' \Vitnesses:

OTTo KoNro, J A. R1TTERsHAUs. 

